Near surface electrical resistivity structures around an active fault trace in Weh Island, Indonesia

Abstract

Near-surface investigation has been carried out in Cot Abeuk, Weh Island, Indonesia. The area is part of the Seulimeum segment active fault, the northernmost branch of the Great Sumatran Fault. We measured two parallel electrical resistivity tomography profiles on the area with the direction perpendicular to the fault strike. The length of profile 1 and profile 2 are 111 m and 125 m, respectively, with 1 meter spacing between electrodes. Along the Profile 2, VLF-EM and Geomagnetic data were also acquired for complementary. The 2D inverted resistivity models show some minor fractures, which can be related to ruptures in the past. The structure was made by weathering rocks, clay and andesite. The models align with the analytic signal of total magnetic field anomalies as well as in-phase, Fraser filter and conductivity model derived from VLM-EM data. Following the successful models, this location is a potential candidate for paleo-seismological excavation.

Keywords

• shallow structure
• rapture
• seulimeum segment
• great sumatran fault
• paleo-seismic